Pinpoint Test V: LFC 57 DTC B2984/B2987
Air Bag and Safety Belt Pretensioner Supplemental Restraint System (SRS)
Pinpoint Tests
Pinpoint Test V: LFC 57 DTC B2984/B2987
Refer to Wiring Diagram Set 46, Supplemental Restraint System for schematic and connector information. Diagrams By Number
NOTE: If the deployable steering column electrical connector becomes damaged or the deployable steering column has deployed, a new overlay wiring harness must be installed. Make sure to follow the installation instructions that are included in the service kit.
Normal Operation
The Restraints Control Module (RCM) will deploy (collapse) the steering column during a frontal collision when seat position information and other parameters reach predetermined limits.
The RCM continuously monitors deployable steering column circuits for an acceptable resistance range. If a fault is detected, the RCM will store DTC (B2984 or B2987) in memory and send a message to the Instrument Cluster (IC) module to flash a Lamp Fault Code (LFC) 57 on the air bag warning indicator. After the LFCs are displayed, the air bag warning indicator will remain illuminated for the rest of the ignition cycle.
The RCM monitors deployable steering column circuits for resistance and expects a normal resistance between 1.50 and 3.04 ohms.
If resistance is between 1.04 and 1.50 ohms or between 3.04 and 3.72 ohms, there exists a strong potential for a fault to occur (a DTC may or may not set). The RCM will also set DTC B2984 or B2987 respectfully if the loop resistance is less than 1.04 ohms or greater than 3.72 ohms.
- DTC B2984 Deployable Steering Column Circuit Open - If the RCM detects an open either deployable steering column circuit, it will set this DTC.
- DTC B2987 Deployable Steering Column Circuit Resistance Low On Squib - If the RCM detects a short between the deployable steering column circuits, it will set this DTC.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Deployable steering column
- RCM
PINPOINT TEST V: LFC 57 DTC B2984/B2987
WARNING: Do not handle, move or change the original horizontal mounting position of the restraints control module (RCM) while the RCM is connected and the ignition switch is ON. Failure to follow this instruction may result in the accidental deployment of the Safety Canopy(R) and cause serious personal injury or death.
WARNING: Never probe the electrical connectors on air bag, Safety Canopy(R) or side air curtain modules. Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when making measurements. Failure to use the correct probe adapter(s) may damage the connector. Most faults are due to connector and/or wiring concerns. Carry out a thorough inspection and verification before proceeding with the pinpoint test. Inspection and Verification
NOTE: Supplemental Restraint System (SRS) components should only be disconnected or reconnected when instructed to do so within a pinpoint test step. Failure to follow this instruction may result in incorrect diagnosis of the SRS.
NOTE: The SRS must be fully operational and free of faults before releasing the vehicle to the customer.
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V1 RETRIEVE RCM DTCs
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC B2984 or B2987 retrieved on-demand during self-test?
Yes
This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test. GO to V2.
No
This is an intermittent fault when present as a CMDTC only. GO to V10.
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V2 CHECK THE DEPLOYABLE STEERING COLUMN
- Enter the following diagnostic mode on the scan tool: DataLogger - RCM .
- Enter the following diagnostic mode on the scan tool: COL_RES PID .
- Does PID value read between 1.50 and 3.04 ohms?
Yes
GO to V9.
No
GO to V3.
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V3 CHECK THE DEPLOYABLE COLUMN RESISTANCE (COL_RES) PID WHILE CARRYING OUT A HARNESS TEST
NOTE: A PID that reads between 1.04 and 1.50 ohms or between 3.04 and 3.72 ohms may or may not set an on-demand DTC, yet indicates a strong potential of an intermittent fault condition. Make sure to thoroughly check wire harness(es), connectors and terminals as they are the likely source of the fault condition.
- While monitoring the COL_RES PID carry out a harness test of the deployable column circuits and accessible connectors (including any in-line connectors), by wiggling connectors and flexing the wire harness.
- Does PID value read between 1.50 and 3.04 ohms while carrying out a harness test?
Yes
DEPOWER the SRS and REPAIR the connector, terminals or wire harness as needed.
Refer to Wiring Diagram Set 5, Connector Repair Procedures for schematic and connector information. Diagrams By Number
GO to V11.
No
If the COL_RES PID is less than 1.50 ohms, GO to V7.
If the COL_RES PID is greater than 3.04 ohms, GO to V4.
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V4 CHECK THE DEPLOYABLE COLUMN FOR AN OPEN FAULT
NOTE: This pinpoint test step will attempt to change the fault reported by the RCM by inducing a different fault condition. If the fault reported changes, this indicates the RCM is functioning correctly and is not the source of the fault.
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Deployable Steering Column C2360.
- Connect a fused jumper wire between deployable steering column C2360 pins 1 and pin 2, harness side.
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- DIAGNOSTIC TIP: When viewing on-demand DTCs with the deployable steering column circuits shorted together, a low resistance fault (B2987) would normally be retrieved.
- Did the on-demand DTC change from B2984 to B2987?
Yes
INSTALL a new steering column assembly. GO to V11.
No
GO to V5.
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V5 CHECK THE DEPLOYABLE STEERING COLUMN CIRCUIT FOR AN OPEN
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: RCM C310a and C310b.
- Remove the fused jumper wire from deployable steering column C2360.
- Measure the resistance between RCM C310a-19, circuit CR168 (WH/GN), harness side and deployable steering column C2360-1, circuit CR168 (WH/GN), harness side.
- Is the resistance less than 0.5 ohm?
Yes
GO to V6.
No
REPAIR circuit CR168 (WH/GN). GO to V11.
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V6 CHECK THE DEPLOYABLE STEERING COLUMN CIRCUIT FOR AN OPEN
- Measure the resistance between RCM C310a-20, circuit RR168 (BU/WH), harness side and deployable steering column C2360-2, circuit RR168 (BU/WH), harness side.
- Is the resistance less than 0.5 ohm?
Yes
GO to V9.
No
REPAIR open in circuit RR168 (BU/WH). GO to V11.
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V7 CHECK FOR A SHORT BETWEEN DEPLOYABLE STEERING COLUMN CIRCUITS
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Disconnect: Deployable Steering Column C2360.
- Measure the resistance between the deployable steering column C2360-2, circuit RR168 (BU/WH), harness side and C2360-1, circuit CR168 (WH/GN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new steering column assembly. GO to V11.
No
GO to V8.
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V8 CHECK THE RCM FOR LOW RESISTANCE
- Disconnect: RCM C310a and C310b.
- Measure the resistance between RCM C310a pin 19, component side and C310a pin 20, component side.
- Is the resistance greater than 10,000 ohms?
Yes
REPAIR circuits RR168 (BU/WH) and CR168 (WH/GN). GO to V11.
No
GO to V9.
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V9 CONFIRM THE RCM FAULT
NOTE: Make sure all restraint system diagnostic tools, sensor electrical connectors and the RCM electrical connectors are connected before carrying out the self test. If not, DTCs will be recorded.
- Connect: Deployable Steering Column C2360.
- Connect: RCM C310a and C310b (if previously disconnected).
- Repower the SRS. Do not prove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Enter the following diagnostic mode on the scan tool: Self Test - RCM .
- Was DTC B2984 or B2987 retrieved on-demand during self test?
Yes
INSTALL a new RCM and CARRY OUT Programmable Module Installation (PMI). REFER to Restraints Control Module (RCM) Service and Repair. GO to V11. Programming and Relearning
No
In the process of diagnosing the fault, the fault condition has become intermittent. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. REPAIR any intermittent wiring, terminal or connector concerns found. GO to V10.
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V10 CHECK FOR AN INTERMITTENT FAULT
- Enter the following diagnostic mode on the scan tool: Self Test - RCM.
- Was DTC B2984 or B2987 retrieved on-demand during self-test?
Yes
This is a hard fault. The fault condition is now present. This fault cannot be cleared until it is corrected and the DTC is no longer retrieved during the on-demand self test. GO to V3.
No
CHECK for causes of the intermittent fault. ATTEMPT to recreate the hard fault by flexing the wire harness and cycling the ignition key frequently. Do not install any new SRS components at this time. SRS components should only be installed when directed to do so in the pinpoint test. REPAIR any intermittent wiring, terminal or connector concerns found. GO to V11.
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V11 CHECK FOR ADDITIONAL SRS DTCs
- Ignition OFF.
- WARNING: Turn the ignition OFF and wait one minute to deplete the backup power supply. Failure to follow this instruction may result in serious personal injury or death in the event of an accidental deployment.
- Reconnect all SRS components (if previously disconnected).
- If previously directed to depower the SRS, repower the SRS. Do notprove out the SRS at this time. Refer to Supplemental Restraint System (SRS) Depowering and Repowering Supplemental Restraint System (SRS) Depowering and Repowering.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self Test - Restraints.
- NOTE: When selecting Restraints from the Self Test menu, DTCs will be retrieved from the RCM and OCSM.
- Are any RCM and/or OCSM DTCs retrieved on-demand during self-test?
Yes
Do not clear any DTCs until all DTCs have been resolved. GO to the DTC Charts for pinpoint test direction. [1][2]Diagnostic Trouble Code Descriptions
No
CLEAR all RCM and OCSM CMDTCs. PROVE OUT the SRS. Repair is complete. RETURN the vehicle to the customer.
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